WASHINGTON - Seven years have passed since the last time the United States bombed Iraq, but one gripping image lingers - video footage shot on Jan. 17, 1991, the first night of the air war, of a laser-guided bomb plunking straight down the chimney of an Iraqi Air Force building and blowing the place off the map.

If President Clinton resumes the war against Iraq, his highlights-footage may look familiar. For despite reports of a new generation of even deadlier and more accurate ''smart'' bombs, the weapons used this time around will in fact be largely the same, with the same destructive force and potential limitations.

The US Air Force and Navy are building new bombs that almost certainly will be more effective than the old ones. But, despite some recent bullish news reports, most of them have not yet been deployed or built, and those that are in the arsenal exist in relatively small numbers.

The Pentagon started to develop the new ''smarter'' bombs after realizing that the Desert Storm models did not all work as well as it seemed from the dramatic footage broadcast worldwide.

The smart bombs of 1991 - which are also largely the smart bombs of 1998 - represented relatively crude technology. One pilot had to shine a laser beam on a target, while another dropped a bomb equipped with a sensor to track the beam.

Weather was their main obstacle in Desert Storm. Pilots told commanders afterward that the lasers did not work well in the face of clouds, smoke, dust, haze, or high humidity. The beam lost its focus, or simply could not penetrate the murk.

The new generation of weapons might change this situation dramatically. They are guided to a target not by laser beams but by Global Positioning Satellites. Many cars these days have GPS receivers that, hooked up to a mapping system, allow drivers to know their precise positions, give or take a few feet. The new bombs contain a similar GPS receiver. The pilot punches in the coordinates of the target. So, the bomb knows where it is - and where to go. Weather, visibility, and altitude do not matter.

One of these new weapons, the Air Force's GPS-Aided Munition, or GAM, can be loaded inside B-2 Stealth bombers. However, only 108 GAMs have been built - not enough to fill a single B-2.

Another, the Navy's Joint Stand-Off Weapon, or J-SOW, can be carried by F/A-18s. But only 30 to 40 exist, according to one defense official, who added that the system has yet to pass an operational test.

The Joint Direct Attack Munition, or J-DAM, is a kit that converts ''dumb bombs'' into smart ones. But, according to John Pike, weapons analyst with the Federation of American Scientists, it will not enter the arsenal until late this year.

One weapon has been fitted with GPS technology in moderate numbers - the Tomahawk cruise missile. The Tomahawk, at $1.3 million each even in its pre-GPS format, was ''a fiasco'' in Desert Storm, one defense official familiar with its results said. It was guided to a target by a sensor that compared key features of the terrain with a pre-programmed radar flight-path map. The problem was, the Iraqi desert lacks features. The missile often got lost. The Navy fired 307 Tomahawks during Desert Storm, most in the first few days. The Defense Intelligence Agency estimated afterward that there were as many ''no-shows'' - meaning the missiles did not show up anywhere near the target - as there were hits.

Today, about 250 Tomahawk Block 3 missiles, all with GPS guidance, are in the Persian Gulf. One official says they will be ''more successful'' than the old version - though it is unclear how much more. They still rely on TV-screen technology to pick out and hit the target once they get there. According to a study by the General Accounting Office, weather often interfered with that final stage of targeting.

And so, Clinton's war machine will rely on much the same technology as George Bush's. Clinton's may even be less lethal. He is not expected to have full access to the eight massive air bases in Saudi Arabia, which opposes plans to bomb its neighbor. And some of the last war's workhorses - especially the F-111F, which, postwar surveys showed, fired the highest percentage of successful strikes - have been retired.

Then again, these shortfalls might not matter. ''This will probably be a reasonably limited strike, with a limited number of sorties,'' said Colonel Phil Meilinger, a member of the Desert Storm air-planning team, now at the Naval War College. As a result, fewer planes and bombs will be needed.

Desert Storm, after all, was geared to boot Iraq's 300,000-man army out of occupied Kuwait. The first phase of the air campaign was aimed at Saddam Hussein's air-defense systems, communications network, Scud missiles, chemical and nuclear facilities - the military infrastructure that kept him in control. But the next phases focused on wiping out his army in southern Iraq and Kuwait, including three armored divisions that had buried their tanks under reinforced shelters.

Of the 36,245 strikes mounted over the 43-day air war, 24,430 - nearly two-thirds - were fired at the tank divisions. The weapon of choice was the ancient B-52 bomber - which alone dropped one-third of the air war's 88,500 tons of ordnance in Vietnam-style carpet-bombing raids. (Despite that pounding, only about one-third of Iraq's tanks were destroyed before the land war began.)

Clinton will not have to go after the Iraqi Army - or, if he does, the task will be easier, since most of its equipment is sitting out in the open, not dispersed and dug in.

The main missions of this war, if it happens, will more probably resemble just the first phase of Desert Storm. The campaign might begin the same way - F-117 Stealth planes swooping in at night, dropping GBU-27 laser-guided bombs on air-defense sites, military facilities, nearly every type of target.

Other planes launched that first night in 1991 fired more than 200 high-speed anti-radiation missiles, or HARMs, which have sensors that home in on the emissions of anti-aircraft radar. Many other planes dropped unguided bombs on large-area targets where precision was not needed.

The absence of F-111s and Saudi bases might be made up for by the fact that every Navy attack plane on aircraft carriers now carries smart bombs. Almost none did in 1991. The Air Force, too, has boosted its number of smart-bomb planes, from 290 to over 500. In all, the number of laser-guided bombs has grown from 9,000 to about 25,000.

The GAO study concluded that, on average, it took four smart bombs to hit a target. In 20 percent of the cases, it took at least six bombs; in 15 percent, at least 8. This is better than the record of unguided bombs, but far short of the claims - ''one shot, one kill'' - made by Pentagon spokesmen and manufacturers just before and after the war.

A more serious limitation, though, is that even when the bombs hit a target, it was not necessarily destroyed - and when it was destroyed that did not always translate as mission accomplished.

A few weeks before the 1991 air war, military strategists wrote that the first phase would ''result in the disruption of Iraqi command and control, loss of confidence in the government, and a significant degradation of Iraqi military capabilities.'' This will lead, they predicted, to ''the progressive and systematic collapse of Saddam Hussein's entire war machine and regime.''

Nothing of the sort took place.

According to the US Air Force's official five-volume ''Gulf War Air Power Survey,'' 580 air strikes were mounted on command-control targets, 260 against Iraq's leaders and their places of work. Yet, ''despite the lethality and precision of the attacks,'' Saddam's ability to command his forces ''had not collapsed ... The system turned out to be more redundant and more able to reconstitute itself.''

Iraq's mobile Scud missiles were the object of 1,460 air strikes. Yet no evidence shows that a single one was hit.

Facilities where Saddam was thought to be building chemical and nuclear weapons were dealt 970 air strikes. The effect, again, was minimal.

This time, targeteers have learned much more about the chemical and nuclear program. Even so, Eliot Cohen, who directed the Gulf War Air Power Survey and is now professor at the Johns Hopkins University School for Advanced International Studies, said, ''We're still not going to get a lot of them.'' They are hard to hit and harder to find.

If the aim, as Clinton has said, is to ''seriously diminish'' Hussein's ability to build weapons of mass destruction and threaten his neighbors, that's a fairly modest hurdle.

However, some officials worry that Clinton's statement simply reflects what his military advisers say is the most an air war could accomplish. They wonder: Would so limited an assault compel Hussein to cooperate more with the UN inspectors - or irritate him enough to kick them out?

The UN teams have destroyed far more of Iraq's arsenal than Desert Storm's air strikes did - 38,000 chemical weapons, 480,000 liters of chemical agents, 48 missiles, 20,000 liters of biological agents. To the extent the inspectors do not know where the rest of Hussein's arsenal is, officials say, neither do the officers planning the coming air war.